Just when you thought you knew everything there was to know about the Beatles, Ron Howard has uncovered new things about the Fab Four for the upcoming documentary, The Beatles: Eight Days a Week -- The Touring Years.

"This a survival story of these young guys," Howard told ET. "They're boys in the beginning and men at the end, and they've been through an amazing journey."

The film traces John Lennon, Paul McCartney, George Harrison and Ringo Starr from 1962-1966 during the years that they became a phenomenon. Howard was a kid at the time, playing Opie on The Andy Griffith Show, and he (like everyone else) found himself swept up in Beatlemania.

"For my 10th birthday what I wanted was Beatle boots and a Beatle wig," Howard said. "My parents couldn't find Beatle boots, but down at the dime store, Woolworths or someplace, they found a Beatle wig!"

The band took the U.S. by storm when they debuted on American television on The Ed Sullivan Show in New York City on Feb. 9, 1964 -- a performance Howard remembers well.

"I watched that," Howard told ET. "It was so important everybody tuned in. It was amazing."

Despite his illustrious resume, which includes two Oscar wins, Howard has only made one other documentary, Jay Z: Made in America, and was initially daunted with the project because he wasn't sure the Beatles story was one he could tell. He walked away with some gems about the iconic band.

"The police and local governments told them that if they continued to play 10,000-person arenas that they would always have 30 or 40 thousand kids outside clamoring and they couldn't control it," Howard said, explaining that they virtually invented the stadium tour out of necessity. "They had to put them in stadiums."

Howard also learned that they looked out for all of their fans no matter what.

"I didn't know that their first political stand -- their first big controversial issue -- involved what was to be a segregated concert in Jacksonville, Florida," Howard said. "They said, 'Are you kidding me? That's ridiculous.' They couldn't see the logic in it, of course, but they had no idea how controversial it was but they stuck to their guns."

The Beatles: Eight Days a Week will premiere in theaters on Sept. 16 and debut on Hulu Sept. 17.